At 300 K and 1 atm, 15 mL of a gaseous hydrocarbon requires 375 mL air containing 20% O₂ by volume for complete combustion. After combustion the gases occupy 345 mL. Assuming that the water formed is in liquid form and the volumes were measured at the same temperature and pressure, the formula of the hydrocarbon is:

The distillation technique most suited for separating glycerol from spent-lye in the soap industry is :

The reaction of zinc with dilute and concentrated nitric acid, respectively, produces :

The equilibrium constant at 298 K for a reaction A + B $$\leftrightharpoons$$ C + D is 100. If the initial concentration of all the four species were 1M each, then equilibrium concentration of D (in mol L^–1) will be: